Electric switch



H. G. HARTMANN May 8, 1928.

ELECTRIC SWITCH Filed Feb. 1. 1924 Invent, or: Hevm ann G. Hartm arm,

by His Attorney.

Patented .May 8, 1928 UNITED STATES HERMANN G.

PATENT OFFICE.

HARTMANN, or SCHENECTADY, new YORK, ASSIGNOR 'ro GENERAL ELECTRIC COMPANY, A. oonrone'rron OF NEW YORK.

Enno'rnro swiron.

Application filed February 1, 1924. Serial No. 690,080.

My invention relates to improvements in electric switches and 'more particularly to improvements in latching devices and operating implement-s for disconnecting switches.

Disconnecting switches are frequently provided in a line circuit for isolating certain portions thereof or apparatus therein and as so used are not Y ordinarily designed to interrupt the circuit while it is energized. Upon the occurrence of abnormal circuit-con ditions, such as excess current, the disconnecting switches are subject to the reaction ofpowerful magnetic forces which tend to open the switches under circuit conditions for which they are not intended to operate or be operated. Moreover, the disconnecting switches often have to be so mounted that gravity tends to open them, and if the switches are subject to mechanical shocks'or vibrations, they may open. In any event, if the switches should open while the circuit is energized, disastrous results such as destruction of the switches themselves and worse, are liable to occur. As a matterof safety, it is therefore advisableto provide some means for preventing'the opening of a disconnecting switch under the conditions set forth. V V I It is therefore anobject of my invention to provide an improved latching means for locking a disconnecting switch in circuit closed position such that the effect of any tendency for the switch to move tocircuit opening position is to tendto increase the positiveness of the locking.

Another object of my invention is to provide an improved latching means and an improved implement adapted to be operated to actuate the latching means and the disconnecting switch such that the latching means can be released and the switchopened inone continuous movement and such that the switch can be closed with a minimum of wear and-shock on the latching means and the movable member ofthe switch.

A further object of' my invention is to i provide a relatively simple and rugged latching means'which, is readily applicable to disconnecting switches, particularly of the single or multiple knife blade or lever type, irrespective of size and whether single or double throw and which is relatively inexpensive and easily assembled and secured to the switch, structure.

My invention will be better understood For locking the switch blade tin circuit up from the following description taken inco'nnection with the accompanying drawing'and its scope will be pointed out in the appended claims. I

Fig. 1 is a side elevation of a single throw disconnecting switch embodying my invention, Figs. 2, 3, and at illustrate in elevation the relative positions of the switch blade,

latching. member and switch operating implement when the implement is inserted in the opening in the switch blade, when the latching member is released and when the switch blade is moved toward circuit closmg position respectively, Fig. 5' illustrates in perspective an embodiment of my improved switch operating implement, and Fig. 6 is a side elevation of adouble throw disconnectinc switch embodying my invention.

The disconnecting switch shown in Fig. 1 comprises a movable electric current conducting member, such as a switch blade 1 pivoted on a hinge 2' and'arranged in circuit closing position to engage a contact 3. The hinge? and contact 3 may bemounted in any suitable mannerand are shown secured to'insulators t and 5 respectively.

Terminalst for connecting the line to the I switch, may be bolted or otherwise secured to the hinge 2 and contact 3.

For operatingpurposes, the switch blade 1 is provided with an opening 7 preferably adjacent the free end of the blade. 'This opening maybe in the switch blade itself or, as shown, in an eye member 8 pivotally associated with the switch blade. The eye member 8 is arranged for a limited movement. relatively to the switch blade so that upon movement of the eye member in a direction to open the switch, the eye member [engages a projection 9 on the contact 3.

This arrangement provides" a mechanical advantage whereby the 'switch blade 1 can be given an initial movement so as to .pry it loose from the contact 3 in case the blade sticks to the contact because of corrosionor for any otherreason. I

v The switch may also be provided with a bladeguide 10 which may be secured to the contact 3 and which comprises a bifurcated portion 11, between thebifurcations of which the blade. is movable, the free ends of. the bifurcations being suitably flared so as to guide the switch blade andfensure therequisite alinement thereof with the contact 3.

ill

closing position, I provide a pivoted latching member 12 biased for movement transversely of the blade to a position to project over or engage the outer edge of the blade. In order that the effect of any tendency for the switch blade 1 to open will not tend to release the latching member 12 but will, on the contrary,tend to turn the latching member to latching position, the pivot 13 of the latching member 12 is mounted on one side of the longitudinal axis of the switch blade so that the latching member 12 is movable to and from latching position on the opposite side of the blade. This will be clear from Fig. 2

in which it is apparent that, when there 15 any: tendency for the switch blade 1 to be moved in circuit opening direction by magnetic action or otherwise, the force acting on the blade, which may be considered as acting on the latch in line with the longitudinal axis of the blade, exerts a counterclockwise torque whose lever arm is the distance between the pivotal axis of the latching member 12 and the longitudinal axis of the switch blade and which tends to turn the latching member 12. to latching position. As a matter of convenience, the blade guide 10 may comprise a projection portion or flange 1 1 in which the pivot 13 ot the latching member 12 is carried. Any suitable biasing means, such as a torsion spring 15 which may be mounted on the pivot 13 and which has its ends in bearing against the flange 14 and the latching member 12 through a hole 16 therein, may be used. To limit the movement of the latching member and also to prevent overstraining the spring 15, any suitable means such as a stop or pin 17 may be mounted on the flange 14 so as to bear againstone end or the other of a notched portion 18 in the latching member 12.

The latching member 12 is preferably mounted as closely as possible to the portion of the contact 3 which is engaged by the switch blade 1 so as to shorten the length of or reduce the amount-of material in the terminal portion of the contact 3. For this purpose and so that the latching member 12 may readily be released or moved from latching position upon the insertion of an operating implement such as a switch hook in the opening 7 in the eye member or blade, I provide the latching member 12 with a projection 19 arranged when the switch blade 1 is in circuit closing position to project across the opening therein on one side thereof. Then upon the insertion of the operating implement from the opposite side of the blade, the latching member 12 can be moved to clear the blade and the latter moved to circuit opening position.

In order that the latching member 12 can he released and the switch blade moved to circuit opening position in one continuous movement of the operating implement in the direction to open the switch, 1 provide a new and useful operating implement shown in perspective in Fig. 5. This implement is hook shaped and comprises a substantially straight shank port-ion 20 and projecting therefrom at one end an arm 21. The arm 21 is provided with a substantially straight inner edge portion 22 inclined at an acute angle with the shank 20 and another straight outer edge portion 23 substantially perpendicular to the shank 20 and a curved edge portion 2 1 between the two straight portions.

Referring now to Figs. 2 and 3, it will be obvious that when the arm 22 is inserted in the opening in the switch blade from the side thereof opposite the projection 19 on thelatching member and the shank 2O moved in a direction to open the switch, the straigl'it edge 22 will slide or move over the edge of the switch blade opening adjacent the latching member 12 thus moving the latching member to the position shown in Fig. 3 and continued movement of the shank 20 in switch opening direction will move the blade 1 out of engagement with the contact 3. The curved edge portion 24. facilitates entering the arm 21 in the blade eye or opening.

While my improved latching device can be operated with the usual. type of switch operating book by inserting the hook transversely of the'switch opening with sufiicient force to disengage the latching member or by pushing on the hook transversely of the blade, this is not always desirable or easy to do, particularly if the switch hook is on the end of a relatively long slender rod or" insulating material, usually wood, and so flexible as to be relatively useless as a beam. The rods however possess the requisite static properties for service as tension members and it is therefore preferable to use an implement embodying my invention so that one continuous movement or pull on the rod will serve to unlatch the blade and move it to circuit opening position, as this provides greater facility and safety in switching operations.

For closing the switch, the arm 21 is inserted in the opening 7 with the straight edge portion 23 in bearing on the switch blade as shown in Fig. 4. As the blade 1 is moved to circuit closing position, it engages the curved edge of the latching member 12 and pushes it out of latching position to which it returns when the blade is in the position shown in Fig. 2 and the arm 21 or the hook removed from the blade opening.

' The switch shown in Fig. 1 for the purpose of illustrating my invention is of the single throw knife blade type, the movable conducting member or blade 1 comprising two simultaneously movable spaced strips of conducting material arranged to embrace the the broken lines the other.

tongue or lug portions 'of'the hinge-2 and contact 3. A similar swit'charranged for double throw is illustrated 'in Fig. 6 in order to show that my invention is applicable without change to adouble throw' switch.

The full lines in Fig.6 indicate one circuit closing position of the switch blade 1" and While I haves how'n and described only one embodiment of. my invention, 1 do not desire to be limited to 'theexact "arrangement shown and described but seekto cover in the appendedclaims all those modificationstliat fall within'the true spirit ands'copeofmy invention.

What I claim as new and desire to secure by Letters Patent of the United States, is:

1. In an electric switch of the class described, a stationary contact, a pivoted Switchblade arranged to enga e said contact incircuit closing position and provided with an opening, and a pivoted latching to turn said latching-member to latching position. I I

'2'. In an I tact," a switch blade arranged to engage said contact, and a ivotedlatching member for said switch-bla e, the pivot for saidlatching member being so located thatany tendency for said switch to open-increases any-tendenc'y iof saidplatching member to remain closed.

3. In an electric switch-of the class described, a stationary-contact, a'--pivoted I Switch blade arranged in-circuit closing-position to engage said contact and a pivoted latching member biased for movement to latching position whereby to hold said switch blade in circuit closing position, the pivot for said latching member being mounted on one side ofthe longitudinal axis of the switch blade and the latching mem ber movable transversely of the longitudinal axis to and from latching position on the o posite side of the switch blade, whereby t e efiect of any tendency for said switch blade to move to circuit opening position is to tend to turn the latching memberto latching position. I

V 4. In an electric switch of the class described, a stationary contact, a pivoted switch blade provided with anopening near the free end thereof and arranged in-circuit closing position toengage said contact, a latching member pivotally mounted on said contact for movement transversely of said switch blade and biased to latching position 'sition. I I p 5. In an electric switch of the classi de scribed a stationary pcontact, ,aymovable switch blade provided with an opening 1 and. arranged:inncircuit closingposition to engagelsaid contact, a latching memberpivotally mountedson said contact and biased electric switch, a stationary 0011- j V p p r closing POSItIOH, a, pro ect1on on said latchto engage the outer edgeiof said switchgblade -in the-c rcuit closing position thereof whereby to hold the same insaid. position, and a projection on" said latching member arranged in the=circuit closing positionlofvsaid switch blade to project. across the opening? therein on one side thereof whereby upon insertion of-an: instrument in said, opening 7 from the "opposite side of said; switch blade said latching member can i be moved from latching pofor movement to latching position to engage theouter edge'of-saidswitch blade in the circuit closing position thereotjzwherebygto hold the same in said position, saidlatching member being arranged in the circuitclosring position of said switch blade to project across the opening therein onone side thereof whereby upon insertion of an implement insaidopening from the opposite side of said switchblade saidlatching member can be moved iromlatching: position,

. 6. An electric switchcomprising a mov' able circuit controlling r member provided withan opening,a movable latching member ebiased for movement to HI- pOSItIOD tO hold said :circuit controlling member in circuit ing member arranged injthe circuit closing position of said circuit controlling member to project, acrossthef opening therein on one side. thereof, and means adapted to be operated to release said latching member and move said circuit controlling memberto circuit .openinguposition, in one continuous and move the latching member away from said circuit controlling member whereby the circuit, controlling member is free to be movedto circuit opening position;

7. An electric switch comprising a movable circuit controlling member provided with an opening, amovable latching mem ber biased for movement to a position to hold said circuit controlling member in circuit closing position 'and'arranged in the circuit closin position ofsaid circuit controlling mem er to project "across the opening therein on one sidethereof and means adapted to be operated to release saidela tc-hing member and move said circuit controlling membertocircuit opening position. in one continuous movement comprising a. hook having an arm insertable in said opening from the opposite side of said circuit controlling member arranged upon movement of said hook in a direction to move said circuit controlling member to circuit opening position to engage said latching member,

thereby to move the latching member away from said circuit controlling member whereby the circuit controlling member'is tree to be moved to circuit opening position.

8. In an electric switch of the class described, a stationary contact, a pivoted switch blade arranged. in circuit closing position to engage said contact and provided with an opening, a pivoted latching member biased for movement to latching position whereby to lock said switch blade in circuit said switch member being so located that the effect of closing pos1tion,a projection on said latching member arranged in the circuit closingposition of said switchblade to project across the opening therein on one side thereof, and means adapted to be operated to move said latching member from latching position and said switch blade to circuit opening position in one continuous movement comprising a hook having an arm'provided with a substantially straight portion oblique to the shank of the whereby upon insertion of said armin said opening from the opposite side of said switch blade and upon movement of the hook in a direction to move the switch blade to circuit opening position the straight portion of said arm slides over the edge of the opening in said switch blade adjacent the pro jection on saidlatching member and the curved portion of said arm engages and moves said latching member out of latching position.

9; In an electric switch, a contact, a cooperating switch blade provided with an opening, a pivoted latching member for blade, the pivot for said latching hook and a curved portion any tendency for the switch to open is to hold the latching member more firmly in latching position, the latching member beingarranged to project across the opening in the switch blade, and means for releasing the latching member and opening the switch.

10. An electric switch comprising a movable circuit controlling vmember provided with an opening, a latching member for holding the circuit controlling member in thecircuit closing position arranged to pro- 'jcctacross said'opening, and means adapted to be operated to release the latching memher and to move the circuit controlling member to the circuit opening position in one continuous movement comprising afhook having an arm provided with a substantially straight edge oblique to theshank of the hook whereby on insertion of the arm in said opening and on movement of the hook in a direction to open the switch the arm slides over the edge of the opening and moves the latching member from the latching position.

1. An electric switch comprisinga pivoted blade provided with an opening near one end, a latch for holding the blade in the circuit closing position arranged to project across said opening and means adapted to be operated to release the latch and tomove the blade to the circuitopening position in one continuous movement comprising a hook having an arm provided with a substantial- 1 straight inner edge forming anacute angle with the shank of the hook and an outer curved edge whereby on insertion of the arm in said opening and on movement of the hook in a direction to open the switch the inner edge of the arm slides over the edge of the opening and the outer edge of the arm engages and releases the latch.

In witness whereof, I have hereunto set my hand this 30th day of January, 1924.

' HERMANN G. HARTMANN. 

